This paper presents a model of the intonational system of Tongan, an Austronesian language, taking the autosegmentalmetrical theory as its framework. Tongan has lexical stress which appears on the penultimate syllable of prosodic words and is marked postlexically with one of two bitonal pitch accents—a rise, LH*, or a low tone, L*. Measurements show that the first tone of both pitch accents aligns with the stressed syllable onset, while the second tone aligns with the stressed syllable offset. There is evidence for two tonally marked levels of prosodic phrasing in Tongan, the intonational phrase (IP) and the accentual phrase (AP). The IP is about the size of a full utterance or major phrase and is marked by a final boundary tone and are realized on the IPfinal syllable. Four boundary tones have been observed. The smaller unit, the AP, usually contains one lexical word plus preceding functional elements. Two APfinal tones have been observed, realized on the final syllable of the phrase. Lastly, focus is only realized intonationally through increased pitch range on the focused element. Tongan is typologically interesting because it provides another case in a growing list of languages that intonationally marks both head and edge prominence.